JP6211455B2 - Heating device for carburetor - Google Patents

Description

  The present invention relates to an apparatus for heating a carburetor provided in an intake system of an engine.

An intake system of an engine mounted on a portable work machine such as a brush cutter may be provided with a carburetor (vaporizer) that mixes fuel with air to generate an air-fuel mixture.
In this regard, in the engine intake system described in Patent Document 1, a carburetor is connected to an engine cylinder via an insulator. Moreover, in patent document 1, the heat sink is interposed between the insulator and the carburetor.

JP 2001-123888 A

However, in the carburetor as described in Patent Document 1, when the engine is operated under a low temperature (for example, an air temperature of 0 ° C. to 5 ° C.) and a high humidity, heat is taken away by fuel vaporization and icing (freezing). Could occur.
In view of such a situation, an object of the present invention is to suppress the occurrence of icing in a carburetor.

Therefore, the heating device for a carburetor according to the present invention is a device that is provided in an intake system of an engine and heats a carburetor that mixes intake air and fuel to generate an air-fuel mixture. A heating device for a carburetor includes a main body portion that has heat conductivity and is attached to the carburetor, and a high-temperature fluid passage that is provided in the main body portion and flows a fluid having a temperature higher than that of intake air. Wherein said fluid comprises a blanking Robaigasu engine.

According to the present invention, the heat of lube Robaigasu flow hot fluid passage of the warming device for carburetor, through the body portion, the heat is transferred to the carburetor. Thereby, since a carburetor is heated, generation | occurrence | production of icing in a carburetor can be suppressed.

Sectional drawing which shows schematic structure of the engine in 1st Embodiment of this invention. Front view of a heating device for a carburetor in the same embodiment II sectional view of FIG. Sectional drawing which shows schematic structure of the carburetor in embodiment same as the above Explanatory drawing of the nozzle in the same embodiment Schematic explanatory drawing of the engine lubrication device in the same embodiment Schematic explanatory drawing of the engine lubrication device in the second embodiment of the present invention. Schematic explanatory drawing of the engine lubrication device in the third embodiment of the present invention. Sectional drawing which shows schematic structure of the engine in 4th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a schematic configuration of an engine in the first embodiment of the present invention. FIG. 1 shows the engine when the piston is positioned near the top dead center TDC (Top Dead Center).

  The engine 1 is an OHV (Over Head Valve) type four-stroke engine and is air-cooled. The engine 1 includes a cylinder portion 2, a crankcase 3 attached to the lower portion of the cylinder portion 2, and an oil tank 4 disposed at a lower direction position of the crankcase 3.

  The cylinder part 2 has a cylindrical space for sliding the piston 5 in the vertical direction in FIG. In this space, the piston 5 is fitted with a gap slidable in the vertical direction in FIG. That is, the cylinder part 2 accommodates the piston 5 so that reciprocation is possible.

A crank chamber 7 is formed by the cylinder portion 2, the crankcase 3 and the piston 5. That is, the crank chamber 7 is formed by the side surface of the cylinder portion 2 and the cylindrical space on the crankcase 3 side formed by the piston 5 and the space in the crankcase 3. In the crank chamber 7, the volume of the internal space changes as the piston 5 slides.
A combustion chamber 9 is formed by the cylinder head 8, the cylinder part 2 and the piston 5.
The oil tank 4 is provided separately from the crankcase 3 and stores oil for lubricating the engine 1.

A check valve 10 is provided between the oil tank 4 and the crankcase 3 to allow only the oil flow from the crankcase 3 (crank chamber 7) to the oil tank 4.
Here, as the piston 5 moves from the bottom dead center BDC (Bottom Dead Center) to the top dead center TDC, the pressure in the crank chamber 7 becomes negative. Conversely, as the piston 5 moves from the top dead center TDC to the bottom dead center BDC, the pressure in the crank chamber 7 becomes positive. Therefore, when the pressure in the crank chamber 7 is positive, the check valve 10 is opened, and liquid or mist-like oil flows from the crank chamber 7 to the oil tank 4. When the pressure in the crank chamber 7 is negative, the check valve 10 is closed.

  A crank 13 is rotatably supported in the crankcase 3. The crank 13 includes a crankshaft 13a serving as a rotation center, a counterweight, and the like. The piston 5 and the crank 13 are connected by a connecting rod 11. The connecting rod 11 and the piston 5 are rotatably connected. The connecting rod 11 and the crank 13 are rotatably connected. With such a configuration, the piston 5 reciprocates in the cylinder portion 2.

A cylinder head 8 is provided on the upper wall of the cylinder portion 2.
The cylinder head 8 is provided with an intake port 15 and an exhaust port 16. The intake port 15 communicates with the carburetor 30 via the insulator 20 and the heating device 50. The exhaust port 16 communicates with an exhaust muffler (not shown).
The cylinder head 8 is provided with an intake valve 17 that opens and closes the intake port 15. The cylinder head 8 is provided with an exhaust valve 18 that opens and closes the exhaust port 16. Here, the intake valve 17 and the exhaust valve 18 open and close the combustion chamber 9.

The insulator 20 is made of, for example, a cylindrical resin. A passage 21 is formed through the insulator 20. The passage 21 guides the air-fuel mixture from the carburetor 30 to the intake port 15.
A main body 51 of a heating device 50 for the carburetor 30 is interposed between the insulator 20 and the carburetor 30 (a carburetor main body 63 described later). An air-fuel mixture passage 52 through which the air-fuel mixture from the carburetor 30 can flow is formed in the main body 51 of the warming device 50.

Here, the structure of the heating apparatus 50 is demonstrated using FIG.2 and FIG.3.
FIG. 2 is a front view of the heating device 50 in the present embodiment. 3 is a cross-sectional view taken along the line II of FIG.

The heating device 50 includes a main body 51 and a high temperature fluid passage 53.
The main body 51 is formed of a metal such as aluminum. The main body 51 has a flat plate shape having a thickness in the flow direction of the air-fuel mixture.
In the main body 51, the above-described air-fuel mixture passage 52 is formed so as to penetrate in the flow direction of the air-fuel mixture.

  A plurality (two in the figure) of through holes 54 are formed in the main body 51. The main body 51 is attached to the carburetor 30 (the carburetor main body 63 shown in FIG. 4) using a bolt or the like through which the male screw portion is inserted into the through hole 54. Here, in the present embodiment, the main body 51 is attached to the carburetor 30 with the main body 51 in contact with the carburetor main body 63 on the first surface 51a. The insulator 20 is attached to the main body 51 on the second surface 51b side.

A hot fluid passage 53 is formed through the main body 51 so as to avoid the mixture passage 52. The high temperature fluid passage 53 extends substantially parallel to the first surface 51 a of the main body 51. Here, the main body 51 has a thickness capable of penetrating the high temperature fluid passage 53.
In the present embodiment, the high-temperature fluid passage 53 constitutes a part of a blow-by gas feed passage 150 (see FIG. 6) described later. Therefore, blow-by gas containing oil mist flows through the high-temperature fluid passage 53. This blow-by gas is a fluid having a temperature higher than that of the aforementioned intake air. Here, blow-by gas means an unburned mixture.

  Therefore, in the present embodiment, the heat of blow-by gas including oil mist flowing through the high-temperature fluid passage 53 during operation of the engine 1 is transferred to the carburetor 30 (carburetor main body 63) via the main body 51. Thereby, the carburetor 30 is heated.

  Here, the size and shape of the main body 51 can be set in consideration of the amount of heat supplied from the fluid flowing through the high temperature fluid passage 53 to the carburetor 30 via the main body 51. For example, when the amount of heat is excessive, the size and shape of the main body 51 can be set so as to increase the exposure of the main body 51 to the outside in order to release a part of the heat to the atmosphere.

  In the present embodiment, the main body 51 is attached to the carburetor 30 in a state where the main body 51 is in contact with the carburetor main body 63. In addition to this, heat from the main body 51 provided with the high-temperature fluid passage 53 is provided. Can be attached to the carburetor 30 with a cylindrical insulator interposed between the main body 51 and the carburetor main body 63.

  Returning to FIG. 1, the intake passage 100 disposed between the carburetor 30 and the intake port 15 and guiding the air-fuel mixture from the carburetor 30 to the intake port 15 is an air-fuel mixture passage 52 of the main body 51 of the heating device 50. And a passage 21 of the insulator 20. That is, the mixture passage 52 constitutes a part of the intake passage 100.

  An air cleaner 40 is provided on the outer side (upstream side) of the carburetor 30. A filter 41 is disposed in the air cleaner 40. As air passes through the filter 41, dust in the air is removed.

The carburetor 30 is a device that mixes fuel with air (intake air) that has passed through the air cleaner 40 to generate an air-fuel mixture. The carburetor 30 may vaporize liquid fuel to generate an air-fuel mixture. The carburetor 30 can adjust the mixing ratio of air and fuel. The carburetor 30 can adjust the flow rate of the air-fuel mixture.
The carburetor 30 includes a diaphragm fuel pump 60 in order to mix fuel into the air. This diaphragm type fuel pump 60 is driven by pressure fluctuation as power.

In order to supply this power, in this embodiment, the diaphragm chamber 61 of the diaphragm fuel pump 60 and the intake passage 100 or the crank chamber 7 are connected by a communication passage 64 (see FIG. 4). The pressure in the intake passage 100 or the crank chamber 7 is supplied to the diaphragm chamber 61 of the diaphragm fuel pump 60 through the communication passage 64.
The diaphragm fuel pump 60 is provided with a diaphragm 62 that is displaced according to pressure fluctuation.

FIG. 4 shows a schematic configuration of the carburetor 30 including the diaphragm fuel pump 60.
The carburetor 30 includes a carburetor main body 63.
The carburetor body 63 is formed with the communication path 64 described above. A diaphragm chamber 61 is formed on the first side (upper surface in the drawing) of the diaphragm 62. A pump chamber 65 is formed on the second side (lower surface in the drawing) of the diaphragm 62. One end of the communication path 64 is connected to the diaphragm chamber 61. The other end side of the communication passage 64 communicates with the intake passage 100 or the crank chamber 7.

The pump chamber 65 communicates with the fuel inlet 72 via the inlet valve 70. The pump chamber 65 communicates with the metering chamber 81 of the metering diaphragm 80 via an outlet valve 74 and a needle valve 76.
The fuel inlet 72 is connected to a sealed fuel tank (not shown) via a suction pipe (not shown). The fuel tank stores liquid fuel.

The negative pressure generated in the intake passage 100 or the crank chamber 7 acts on the diaphragm chamber 61 via the communication passage 64. The diaphragm fuel pump 60 is driven by the negative pressure acting on the diaphragm chamber 61. More specifically, when a negative pressure acts on the diaphragm chamber 61 of the diaphragm fuel pump 60 and the diaphragm 62 bends toward the diaphragm chamber 61, a negative pressure acts on the pump chamber 65 side. Due to the negative pressure in the pump chamber 65, the inlet valve 70 is opened while the outlet valve 74 is closed, and fuel is sucked into the pump chamber 65 from the fuel inlet 72.
In this manner, in the diaphragm fuel pump 60, the diaphragm 62 is waved by pressure fluctuation (air pulsation) supplied to the diaphragm chamber 61, and the wave movement of the diaphragm 62 causes the pump chamber 65 to move from the fuel tank. Fuel is inhaled.

  Next, when the negative pressure acting on the diaphragm chamber 61 of the diaphragm fuel pump 60 turns to a positive pressure in this state, the diaphragm 62 tries to return to the original state by the elastic action of the diaphragm 62. If it does so, a positive pressure will act on the pump chamber 65 side. When positive pressure acts on the pump chamber 65 side by the movement of the diaphragm 62, the outlet valve 74 is opened while the inlet valve 70 is closed, and fuel is discharged from the pump chamber 65. The discharged fuel is supplied to the metering chamber 81 of the metering diaphragm 80 via the needle valve 76.

  The metering chamber 81 is partitioned from the back pressure chamber 82 by a metalling diaphragm 80. The pressure of the engine 1 acts on the back pressure chamber 82, and the metering diaphragm 80 is driven by a pressure difference between the pressure of the engine 1 and the metering chamber 81. A passage for communicating the back pressure chamber 82 and the negative pressure of the engine is not shown.

  The metering diaphragm 80 is connected to the above-described needle valve 76 via the control lever 84, and the needle valve 76 is opened and closed by the operation of the metering diaphragm 80. Specifically, when the metering chamber 81 is filled with fuel, the pressure of the metering chamber 81 is increased and the metering diaphragm 80 is bent toward the back pressure chamber 82. At this time, due to the elastic force of the control lever spring 86, the control lever 84 rotates so that one end (right side in the figure) is pushed down and the other end (left side in the figure) is pushed up. With this turning operation of the control lever 84, the needle valve 76 is pushed up, and the communication between the pump chamber 65 and the metering chamber 81 is cut off.

The carburetor body 63 is formed with a passage 88 that connects the intake passage 100 and the air cleaner 40. In this passage 88, the upstream side (air cleaner 40 side) is a large diameter portion 88a, and the downstream side (intake passage 100 side) is a venturi portion 88b having a smaller diameter than the large diameter portion 88a. The venturi portion 88b is provided with a throttle valve 90 that displaces the opening degree.
The throttle valve 90 has its rotational axis orthogonal to the passage 88, and rotates while sliding in the vertical direction in the figure by operating the rotation lever 90a, so that the opening degree of the venturi 88b is displaced by the amount of rotation. I have to.

The throttle valve 90 is provided with a first adjuster screw 91 for finely adjusting the amount of fuel mixed with the air flowing through the passage 88 coaxially with the rotating shaft.
The first adjuster screw 91 is provided with a second adjuster screw 92 coaxially with the rotation axis thereof. The second adjustment task screw 92 is provided so as to extend in the vertical direction in the drawing. Further, with respect to the second adjustment task screw 92, the outer dimension is reduced in two steps from the upper side to the lower side from the outer diameter dimension substantially the same as the inner diameter dimension of the nozzle 94 described later.
A switching portion 92 a for switching a main jet 96 described later is provided at the tip of the second adjustment task screw 92.

When the first adjuster screw 91 rotates in one direction (screw tightening direction) with respect to the throttle valve 90, it moves downward in the figure, and conversely, when it rotates in the other direction (screw return direction) with respect to the throttle valve 90, Move upward in the figure.
Similarly to the first adjustment task screw 91, the second adjustment task screw 92 moves downward in the figure when rotated in one direction (screw tightening direction), and conversely, the first adjustment task screw 92 If it rotates to the other side (screw-return direction) with respect to 91, it will move upward in the figure.

  The carburetor body 63 is provided with a nozzle 94 so as to face the second adjuster screw 92, and the tip of the second adjuster screw 92 is inserted into the nozzle tip 94 a of the nozzle 94. The nozzle 94 is formed with a hole 94 b that opens into the passage 88, and a base end 94 c that communicates with the hole 94 b faces the metering chamber 81. A main jet 96 and a main check valve 98 are provided between the hole 94b and the metering chamber 81 as mixing ratio adjusting means and fuel supply amount adjusting means.

FIG. 5 is an explanatory diagram of the nozzle 94.
The main jet 96 has a first main jet portion 96a that communicates the hole 94b of the nozzle 94 and the metering chamber 81 with a predetermined opening area, and a hole 94b and the metering chamber of the nozzle 94 that have a larger opening area than the first main jet portion 96a. 81 and a second main jet part 96 b communicating with 81.

  In the main jet 96, one of the first main jet portion 96a and the second main jet portion 96b is closed by the switching portion 92a of the second adjuster screw 92, and the other communicates the hole 94b of the nozzle 94 and the metering chamber 81. The main jet 96 switches the closing and opening of the first main jet portion 96a and the second main jet portion 96b by rotating the second adjustment task screw 92 with respect to the first adjustment task screw 91. That is, the main jet 96 causes the fuel to flow through one of the first main jet portion 96a and the second main jet portion 96b by rotating the second adjust task screw 92 relative to the first adjust task screw 91 according to the fuel to be used.

Next, the lubricating device of the engine 1 will be described with reference to FIG.
FIG. 6 is a schematic explanatory diagram of the lubricating device for the engine 1 in the present embodiment.

  The oil tank 4 stores oil for lubricating driving components such as the crankshaft 13a and the valve train members. The oil tank 4 and the crank chamber 7 are connected by an oil supply passage 114. The crank chamber 7 and the oil tank 4 are connected by a first oil discharge passage 116 via a check valve 10. Here, in FIG. 1 described above, the first oil discharge passage 116 is not shown.

The valve operating mechanism for driving the intake valve 17 and the exhaust valve 18 includes a valve drive gear 117 fixed to the crankshaft 13a, a cam gear 119 driven by the valve drive gear 117 and having a cam 118, a rocker arm (not shown), and the like. It is composed of parts. Among these valve operating mechanisms, the valve drive gear 117 and the cam gear 119 are accommodated in a drive chamber 121 provided on the side of the cylinder part 2, and the rocker arm is provided with a valve operating chamber (rocker provided above the cylinder part 2). Chamber) 122. Here, among the valve operating mechanisms for driving the intake valve 17 and the exhaust valve 18, components such as a rocker arm housed in the valve operating chamber 22 correspond to “intake / exhaust valve mechanisms” of the present invention.
The drive chamber 121 and the valve operating chamber 122 are connected by a connection passage 123.

  The drive chamber 121 and the oil tank 4 are connected by a second oil discharge passage 125. The oil supply passage 114 and the second oil discharge passage 125 are connected by a flow rate adjustment passage 126. A flow restrictor 127 is provided in the flow rate adjusting passage 126.

  The oil supply passage 114 is connected to the flexible tube 132 inside the oil tank 4. A weight 133 is attached near one end of the flexible tube 132, and one end of the flexible tube 132 functions as the oil absorption port 134. Then, whatever the posture of the engine 1, the oil inlet 134 of the oil supply passage 114 is submerged under the oil level by the weight 133.

  The oil supply passage 114 and the crank chamber 7 are connected so as to communicate with each other only when the piston 5 is near the top dead center, and the oil supply passage 114 is closed by the piston 5 at other timings. The oil supply passage 114 is provided with a one-way valve 99 that allows oil to flow only from the oil tank 4 toward the crank chamber 7. By adopting such a configuration, it becomes possible to sufficiently supply oil from the oil tank 4 to the crank chamber 7 using the negative pressure of the crank chamber 7 regardless of the posture of the engine 1. The crankshaft 13a and the piston 5 can be sufficiently lubricated.

The excess oil in the crank chamber 7 is collected in the oil tank 4 through the first oil discharge passage 116 when the check valve 10 is opened.
The mist-like oil (oil mist) in the oil tank 4 is supplied to the drive chamber 121 through the second oil discharge passage 125 and further supplied to the valve chamber 122 through the connection passage 123. The oil mist lubricates each component constituting the valve operating mechanism.

  A plurality of suction pipes 136 are provided in the valve train chamber 122 to suck the oil accumulated in the valve train chamber 122. The suction pipe 136 and the connecting passage 137 are connected. The connecting passage 137 is provided on the opposite side of the valve chamber 122 from the crank chamber 7. The suction pipe 136 is provided so as to communicate with the connecting passage 137 and extend toward the crank chamber in the valve operating chamber 122, and the tip of the suction pipe 136 is open. The tip of the opening of the suction pipe 136 is disposed near the crank chamber side bottom surface of the valve operating chamber 122 in order to suck up oil from the crank chamber side bottom surface in the valve operating chamber 122. The suction pipe 136 is disposed at the corner of the valve operating chamber 122, and even if the engine 1 is tilted in a state where the valve operating chamber 122 is positioned above, the suction pipe 136 is inserted into the valve operating chamber 122 via any of the suction pipes 136. The oil accumulated in the can be sucked.

A plurality of small holes 138 are provided in the connection passage 137. The small hole 138 is disposed at the corner of the valve operating chamber 122 opposite to the crank chamber 7, and even if the engine 1 is tilted in a reverse state where the valve operating chamber 122 is positioned below, any of the small holes 138 is provided. The oil accumulated in the valve operating chamber 122 can be sucked through the valve.
The connection passage 137 is provided with a one-way valve 139 that allows oil to flow only from the valve operating chamber 122 toward the crank chamber 7.

  A direct passage 140 is provided in the connection passage 137. The direct passage 140 and the crank chamber 7 are connected to communicate with each other only when the piston 5 is in the vicinity of the top dead center, and the direct passage 140 is closed by the piston 5 at other timings. By adopting such a configuration, the valve chamber 122 can be sufficiently transferred from the valve chamber 122 to the crank chamber 7 by utilizing the negative pressure at which the pressure of the crank chamber 7 is substantially in the lower limit regardless of the posture of the engine 1. The oil can be sucked into the valve chamber and oil can be prevented from accumulating more than necessary in the valve operating chamber 122.

  Here, the oil return passage 141 includes a suction pipe 136, a connection passage 137, and a direct passage 140. The oil return passage 141 has one end connected to the valve operating chamber 122 and the other end connected to the cylinder part 2. In the oil return passage 141, oil from the valve operating chamber 122 flows. The oil flowing through the oil return passage 141 is a fluid having a temperature higher than that of the intake air.

  The gas-liquid separator 142 is provided in the air cleaner 40. The valve operating chamber 122 and the gas-liquid separator 142 are connected by a blow-by gas feed passage 150. Here, blow-by gas containing oil mist flows through the blow-by gas feed passage 150. Further, the blow-by gas including oil mist flowing through the blow-by gas feed passage 150 is a fluid having a temperature higher than that of the intake air.

  The blow-by gas containing oil mist is sent to a gas-liquid separation device 142 formed of a wire mesh or the like through a blow-by gas feed passage 150. The gas-liquid separator 142 separates oil and blow-by gas by adhering the oil content in the blow-by gas to a wire mesh or the like.

  The gas-liquid separator 142 and the crank chamber 7 are connected by a reflux passage 152. The oil separated from the blow-by gas by the gas-liquid separator 142 is sent to the crank chamber 7 through the reflux passage 152.

The gas-liquid separator 142 and the air passage in the air cleaner 40 are connected by a blow-by gas discharge passage 160. Here, in the blow-by gas discharge passage 160, the blow-by gas after gas-liquid separation by the gas-liquid separator 142 (in other words, after the oil component is separated) flows. The blow-by gas flowing through the blow-by gas discharge passage 160 is a fluid having a temperature higher than that of the aforementioned intake air.
The blowby gas separated by the gas-liquid separation device 142 is sent to the combustion chamber 9 through the air passage in the air cleaner 40, the passage 88 of the carburetor 30, the intake passage 100, and the intake port 15.

  The recirculation passage 152 and the crank chamber 7 are connected so as to communicate with each other only when the piston 5 is near the top dead center, and the recirculation passage 152 is closed by the piston 5 at other timings. The recirculation passage 152 is provided with a one-way valve 154 that allows oil to flow only from the gas-liquid separator 142 toward the crank chamber 7. With such a configuration, it becomes possible to sufficiently suck oil from the gas-liquid separator 142 into the crank chamber 7 using the negative pressure of the crank chamber 7, and blow-by gas discharge from the gas-liquid separator 142. The oil can be prevented from being discharged into the passage 160, and the early consumption of the oil can be suppressed.

  Here, the first oil lubrication path 171 through which the lubricating oil circulates is the oil tank 4, the second oil discharge passage 125, the drive chamber 121, the connection passage 123, the valve train chamber 122, the blow-by gas feed passage 150, the gas-liquid. The separator 142, the reflux passage 152, the crank chamber 7 (cylinder part 2), and the first oil discharge passage 116 are configured. Therefore, the valve operating chamber 122, the blow-by gas feed passage 150, and the gas-liquid separation device 142 constitute a part of the first oil circulation path 171.

  The second oil lubrication path 172 through which the lubricating oil circulates includes the oil tank 4, the second oil discharge path 125, the drive chamber 121, the connection path 123, the valve operating chamber 122, the oil return path 141 (suction pipe 136, The connecting passage 137 and the direct passage 140), the crank chamber 7 (cylinder portion 2), and the first oil discharge passage 116 are configured. Therefore, the valve operating chamber 122, the oil return passage 141, and the cylinder part 2 constitute a part of the second oil circulation path 172.

  In the present embodiment, as shown in FIG. 6, the high-temperature fluid passage 53 of the heating device 50 constitutes a part of the blow-by gas feed passage 150 (in other words, an intermediate part). Further, the high-temperature fluid passage 53 of the heating device 50 constitutes a part of the first oil circulation path 171 (in other words, an intermediate part). Thereby, the temperature reduction of the carburetor 30 is suppressed by the heat of the blow-by gas during the operation of the engine 1, so that the occurrence of icing in the carburetor 30 can be suppressed. In addition, since the oil mist in the blow-by gas is cooled by the carburetor 30 and liquefaction is promoted, the oil recovery rate in the gas-liquid separator 142 can be improved. Therefore, it is possible to reduce the contamination of the air cleaner 40, reduce the oil consumption, and reduce the carbon adhesion in the combustion chamber 9.

  According to the present embodiment, the heating device 50 for the carburetor 30 is a device that is provided in the intake system of the engine 1 and heats the carburetor 30 that mixes intake air and fuel to generate an air-fuel mixture. The heating device 50 includes a main body 51 that has heat conductivity and is attached to the carburetor 30, and a high-temperature fluid passage 53 that is provided in the main body 51 and through which a fluid having a temperature higher than that of intake air flows. The The fluid is at least one of lubricating oil and blow-by gas for the engine 1. Thereby, since the carburetor 30 is heated, generation | occurrence | production of icing in the carburetor 30 (especially generation | occurrence | production of icing in the nozzle 94 vicinity of the carburetor 30) can be suppressed.

  Further, according to the present embodiment, the high temperature fluid passage 53 constitutes a part of the first oil circulation path 171 through which the lubricating oil circulates. Thereby, since the temperature rise of oil can be suppressed, suppression of deterioration of oil and suppression of the fall of lubrication performance are realizable.

  Further, according to the present embodiment, the engine 1 includes a valve operating chamber 122 that accommodates intake and exhaust valve mechanisms, and one end portion connected to the valve operating chamber 122, and lubricating oil from the valve operating chamber 122. A blow-by gas feed passage 150 through which blow-by gas circulates, and a gas-liquid separation device 142 that is connected to the other end of the blow-by gas feed passage 150 and separates lubricating oil and blow-by gas are configured. . The valve operating chamber 122, the blow-by gas feed passage 150, and the gas-liquid separator 142 constitute a part of the first oil circulation path 171. The hot fluid passage 53 constitutes a part of the blow-by gas feed passage 150. As a result, the oil mist in the blow-by gas is cooled by the carburetor 30 and liquefaction is promoted, so that the oil recovery rate in the gas-liquid separator 142 can be improved.

  Further, according to the present embodiment, the main body 51 of the heating device 50 is disposed between the carburetor 30 and the intake port 15 of the engine 1 and attached to the carburetor 30. Thereby, the 1st oil circulation path 171 including the high temperature fluid channel | path 53 of the heating apparatus 50 can be made into a compact structure.

Further, according to the present embodiment, the engine 1 includes the intake passage 100 that is disposed between the carburetor 30 and the intake port 15 and guides the air-fuel mixture from the carburetor 30 to the intake port 15. The main body 51 includes an air-fuel mixture passage 52 through which air-fuel mixture can flow. The mixture passage 52 constitutes a part of the intake passage 100. Thereby, the enlargement of the intake system accompanying the installation of the heating device 50 can be suppressed.

FIG. 7 is a schematic explanatory diagram of a lubricating device for the engine 1 according to the second embodiment of the present invention.
Differences from the first embodiment will be described.

  In the present embodiment, the high-temperature fluid passage 53 of the heating device 50 constitutes a part of the direct passage 140 (in other words, an intermediate part). That is, the high-temperature fluid passage 53 of the heating device 50 constitutes a part of the oil return passage 141 (in other words, an intermediate part). Further, the high-temperature fluid passage 53 of the heating device 50 constitutes a part of the second oil circulation path 172 (in other words, an intermediate part) through which lubricating oil circulates. Thereby, the temperature reduction of the carburetor 30 is suppressed by the heat of the oil collected from the valve operating chamber 122 during the operation of the engine 1, so that the occurrence of icing in the carburetor 30 can be suppressed.

  In particular, according to the present embodiment, the engine 1 includes a valve operating chamber 122 that accommodates intake and exhaust valve mechanisms, and one end connected to the valve operating chamber 122 so that lubricating oil from the valve operating chamber 122 is supplied with lubricating oil. The oil return passage 141 that circulates and the cylinder portion 2 that is connected to the other end portion of the oil return passage 141 and accommodates the piston so as to reciprocate can be configured. The valve operating chamber 122, the oil return passage 141, and the cylinder part 2 constitute a part of the second oil circulation path 172. The high temperature fluid passage 53 constitutes a part of the oil return passage 141. Thereby, since the oil heated in the valve operating chamber 122 is cooled by the carburetor 30, an excessive increase in the temperature of the oil is suppressed, thereby suppressing the deterioration of the oil and the decrease in the lubricating performance of the oil. Can be realized.

FIG. 8 is a schematic explanatory diagram of the lubricating device for the engine 1 according to the third embodiment of the present invention.
Differences from the first embodiment will be described.

  In the present embodiment, a portion (in other words, a midway portion) between one end side (the gas-liquid separator 142 side) and the other end side (the air passage side in the air cleaner 40) of the blow-by gas discharge passage 160 is an air cleaner. A detour is made so as to be away from 40, and this detour portion is constituted by a high-temperature fluid passage 53 of the heating device 50.

  In particular, according to the present embodiment, the engine 1 includes a valve operating chamber 122 that accommodates intake and exhaust valve mechanisms, one end of which is connected to the valve operating chamber 122, and lubricating oil from the valve operating chamber 122. The blow-by gas feed passage 150 through which the blow-by gas flows, the gas-liquid separation device 142 that separates the lubricating oil and the blow-by gas are connected to the other end of the blow-by gas feed passage 150, and after the gas-liquid separation And a blow-by gas discharge passage 160 through which the blow-by gas flows. The hot fluid passage 53 constitutes a part of the blow-by gas discharge passage 160. Thereby, the temperature reduction of the carburetor 30 is suppressed by the heat of the blow-by gas during the operation of the engine 1, so that the occurrence of icing in the carburetor 30 can be suppressed. Further, the blow-by gas from which the oil component has been separated by the gas-liquid separation device 142 is cooled by the carburetor 30 to reduce its volume. Due to the decrease in the volume of the blow-by gas, the mixing ratio of the blow-by gas to the fresh air sucked from the air cleaner 40 is relatively lowered, so that fluctuations in the air-fuel ratio due to the blow-by gas can be suppressed. Stabilization of rotation can be realized.

FIG. 9 is a cross-sectional view showing a schematic configuration of the engine 1 according to the fourth embodiment of the present invention.
Differences from the first to third embodiments will be described.

  In the present embodiment, the intake passage 180 and the heating device 50 are interposed between the air cleaner 40 and the carburetor 30 in order from the upstream side to the downstream side. That is, in the present embodiment, the heating device 50 is attached to the upstream side of the carburetor 30. Even with such a configuration, since the carburetor 30 is heated, the occurrence of icing in the carburetor 30 (particularly, the occurrence of icing in the vicinity of the nozzle 94 of the carburetor 30) can be suppressed.

  For attaching the heating device 50 to the carburetor 30, the heat of the lubricating oil and / or blow-by gas flowing through the high-temperature fluid passage 53 of the heating device 50 is transferred to the carburetor 30 via the main body 51. Needless to say, this is not limited to the attachment method shown in the first to fourth embodiments.

  Moreover, the engine 1 in the first to fourth embodiments described above can be mounted as a drive source on a portable working machine such as a brush cutter, a digger, or a concrete cutter. The engine 1 can be mounted as a drive source on a backpack type work machine such as a backpack blower, a sprayer (sprayer), a dusting machine, or a backpack type brush cutter.

  As can be seen from the foregoing, the illustrated embodiments are merely illustrative of the present invention, and the present invention is made by those skilled in the art within the scope of the claims in addition to those directly illustrated by the described embodiments. Needless to say, it includes various improvements and changes.

DESCRIPTION OF SYMBOLS 1 Engine 2 Cylinder part 3 Crankcase 4 Oil tank 5 Piston 7 Crank chamber 8 Cylinder head 9 Combustion chamber 10 Check valve 11 Connecting rod 13 Crank 13a Crankshaft 15 Intake port 16 Exhaust port 17 Intake valve 18 Exhaust valve 20 Insulator 21 Passage 30 Carburetor 40 Air Cleaner 41 Filter 50 Heating Device 51 Main Body 52 Mixture Passage 53 High Temperature Fluid Passage 54 Through Hole 60 Diaphragm Fuel Pump 63 Carburetor Main Body 88 Passage 94 Nozzle 100 Intake Passage 122 Valve Valve Chamber 140 Direct Passage Passage 141 Oil Return Passage 142 Gas-liquid separator 150 Blow-by gas feed passage 160 Blow-by gas discharge passage 171 First oil circulation path 172 Second oil circulation path 180 Intake passage

Claims (7)

An apparatus for heating a carburetor, which is provided in an intake system of an engine and mixes intake air and fuel to generate an air-fuel mixture,
A main body having heat conductivity and attached to the carburetor;
A high-temperature fluid passage provided in the main body and through which a fluid having a higher temperature than the intake air flows;
Comprising
Wherein the fluid comprises a blanking Robaigasu engine warming device for carburetor. 2. The heating device for a carburetor according to claim 1, wherein the fluid further includes an oil for lubricating an engine and is in a mist form. 3. The heating device for a carburetor according to claim 2 , wherein the high-temperature fluid passage constitutes a part of an oil circulation path through which the lubricating oil circulates. The engine is
A valve chamber that houses the intake and exhaust valve mechanisms;
One end portion is connected to the valve operating chamber, and a blow-by gas feed passage through which the lubricating oil and the blow-by gas from the valve operating chamber circulates,
A gas-liquid separator that is connected to the other end of the blow-by gas feed passage to separate the lubricating oil and the blow-by gas;
Comprising
The valve operating chamber, the blow-by gas feed passage, and the gas-liquid separator constitute a part of the oil circulation path,
The heating device for a carburetor according to claim 3 , wherein the high-temperature fluid passage forms a part of the blow-by gas feed passage. The engine is
A valve chamber that houses the intake and exhaust valve mechanisms;
One end is connected to the valve operating chamber, a blow-by gas feed passageway and lubrication oil from the valve operating chamber and the blow-by gas flows,
A gas-liquid separator that is connected to the other end of the blow-by gas feed passage to separate the lubricating oil and the blow-by gas;
A blow-by gas discharge passage through which the blow-by gas after gas-liquid separation flows;
Comprising
The heating device for a carburetor according to claim 1, wherein the high-temperature fluid passage forms a part of the blow-by gas discharge passage.   The said main-body part is a heating apparatus for carburetors as described in any one of Claims 1-5 arrange | positioned between the said carburetor and the intake port of the said engine, and being attached to the said carburetor. The engine includes an intake passage that is disposed between the carburetor and the intake port and guides the air-fuel mixture from the carburetor to the intake port.
The main body includes a mixture passage through which the mixture can flow,
The heating device for a carburetor according to claim 6, wherein the air-fuel mixture passage forms a part of the intake passage.